Organizers of the famed Newport Beach-to-Ensenada sailing regatta were stunned by the mysterious loss of four crew members aboard a 37-foot boat that disappeared in mid-race, marking the first fatalities in the event's 65-year history.

While the U.S. Coast Guard was still investigating the accident, regatta organizers said they believed the boat was hit and demolished by a much larger ship — perhaps a freighter or tanker — passing in the dark early Saturday.

The boat disappeared from the online tracking system around 1:30 a.m. Saturday. Two sailors on other boats recalled seeing a large ship in the area.

"We're all in shock," said Chuck Iverson, commodore of the Newport Ocean Sailing Assn., sponsor of the 125-mile race, which is one of the sport's most popular. "We're still trying to piece it together and find out more from the investigation."

Three bodies were recovered Saturday from a scattered debris field near the Coronado Islands, about 15 miles south of San Diego. None was wearing a life jacket.

After scouring a 600-square-mile area Sunday with ships and aircraft, the Coast Guard on Sunday night suspended its search indefinitely for the fourth crew member. "We've exhausted all possibilities," said a spokesman.

The Coast Guard has yet to determine a cause for the apparent destruction of the boat, called the Aegean. But racing officials believe it was struck by a "much larger vessel".

The Coast Guard's lead investigator for San Diego, Bill Fitzgerald, said investigators were "tracking down any vessel that may have been in their area."

The deaths were the first in the history of the race, which this year had 213 entries and has a history of attracting such world-class skippers as Dennis Conner, Bill Ficker and Dave Ullman, as well as celebrities like Walter Cronkite, Buddy Ebsen and Humphrey Bogart.

The destruction of the Aegean comes two weeks after a 38-foot sailboat was swamped by two rogue waves during a race around the Farallon Islands off San Francisco. Five of the eight crew members were killed.

Despite these two disasters, statistics kept by the Coast Guard indicate that even though the waters off the West Coast are heavily used by recreational boaters, merchant ships and U.S. Navy vessels, accidents are exceedingly rare.

In 2010, the latest year for which statistics were available, six accidents involving recreational boaters were reported to the Coast Guard three miles or more into the Pacific Ocean — with only one fatality.

On Sunday, anguished family members of the four Aegean crew members waited for an explanation.

Rudolph was a co-worker with the sailboat owner and skipper Theo Mavromatis. He was not an avid sailor but had taken up the sport in recent years and enjoyed the challenge and camaraderie.

Rudolph had done the Newport-to-Ensenada race three times, his wife said.

"There is nobody like him," Leslie Rudolph said from their Manhattan Beach home. "He's special, he brought joy to everyone."

The San Diego County medical examiner identified two of the victims as Joseph Lester Stewart, 64, of Bradenton, Fla., and William Reed Johnson, 57, of Torrance.

Mavromatis' family declined to speak to a reporter inquiring whether he was aboard his boat.

The Aegean crew members had been uploading pictures and posts to a website so that friends and family members could trace their progress. Organizers had an online tracking system to keep them apprised of the boats, which had left Newport on Friday amid festivities.

When the Aegean's image vanished from the system early Saturday morning, organizers contacted the Coast Guard.

By mid-morning, a debris field was located, including the rear transom with the boat's name on it. Two of the three bodies were found by civilian boaters. The bodies were airlifted to the San Diego County medical examiner's office for identification.

The Coast Guard and Mexican navy continued searching through Saturday night, joined at daybreak by Coast Guard aircraft. Civilian boaters reported the debris field, which consisted of small chunks of wood, suggesting that the Aegean had been rammed and demolished.

Eric Lamb, who works for Vessel Assist, a private maritime assistance firm, was one of the first on scene, spotting a small refrigerator, a seat cushion and some food containers in the water. The two bodies, he said, had cuts and bruises and looked as if they had been dragged along the hull of the boat.

He said the debris "looked like it had gone through a blender."

The debris does not suggest an explosion, said sailing association spokesman Rich Roberts. To leave the Aegean in such small pieces, he said, the other ship would have had to be "much larger."

David Lee, one of the competitors and a part-time sailing instructor at UC Irvine, said it is not uncommon to see large vessels during the race: cruise ships, Navy ships and freighters. "We saw all three types this year," said Lee, whose sloop was not close to the Coronado Islands.

"These vessels can travel at speeds of 20 knots, covering a mile in just three minutes,"Lee said in a text message from Ensenada. "As yacht racers, we must keep a sharp lookout to determine the speed and direction of this traffic and to take early and decisive action to avoid the risk of collision."

Sailboats, Lee said, "have relatively poor visibility on ship's radar and it would be impossible for a ship to track the multitude of targets in any event. A sailboat's navigation lights can be lost against a brightly lit shoreline."

Sea conditions were discounted as a possible cause. The Coast Guard said visibility was good and ocean swells were a modest 6 to 8 feet.

The mood was somber Sunday afternoon at the Bahia Corinthian Yacht Club in Newport Beach. The club Thursday hosted the send-off party for race participants.

"The sailing community being a tight-knit community — it affects everybody," said Paul Secard, 58, who has participated in several of the races.

Secard said there are usually two people on the boat watching out for tankers or other big vessels during such races. Still, he said it's difficult to see what is around you at night.

"Nobody wants anyone injured at all, much less somebody losing their lives, for crying out loud," he said. "It's supposed to be three days of fun."

The Aegean was a Hunter 376. Mavromatis, the owner-skipper, is president and chief executive officer of Aegean Consulting Inc., which specializes in the telecommunications and aerospace industries.

The Newport-to-Ensenada race, which grew to bill itself as "the world's largest international yacht race," began in 1947 for sailboat enthusiasts fresh from the grim days of World War II. As it gained notice in the sailing community, the race began to attract both serious professionals and equally serious amateurs and hobbyists.

A boat owned by Roy E. Disney held the record for monohulls for several years. The 60-foot Stars and Stripes catamaran owned by business tycoon/adventurer Steve Fossett set a multihull record in 1998.

The race includes several classes and multiple awards and trophies. As the winners were announced Sunday afternoon in Ensenada, a gloomy moment of silence was observed for the four from the Aegean.